Explore the largest pure gypsum deposit in the world, and go dune sledding while you're at it.

Twice a year, visitors can tour the desolate site that birthed the Atomic Age.

The final resting place of the living embodiment of the famous Forest Service symbol.

In a largely deserted ghost town, a little brick building recalls its history as a gold rush hub and haven for outlaws.

Steep canyon walls hide a forested oasis in the West Texas desert.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

This fast-food outlet is the only space and UFO-themed McDonalds in the world.

Wee (and not so wee) footprints that insects and reptiles of the Paleozoic Era left behind.

A giant "X" symbolizes the blood spilled from the brutal Juárez drug wars.

The wreckage of a crash that killed nine people still litters the Franklin Mountains.

The house's confection-like decorations are the result of one man's painstaking work over decades.

Natural catch-basin rocks covered in thousands of drawings spanning many millennia.

More than 21,000 images fill this overlooked gem of a prehistoric site.

Buried beneath the New Mexico sands are believed to be millions of copies of Atari's E.T. video game.

This is one really big nut.

The strange phenomenon causing gravity to "work backwards" on this hill has been blamed on the paranormal.

Nuclear reactor created the plutonium used on Nagasaki.

A 1940s nuclear reactor built to produce plutonium for the Manhattan Project.

Home to the deepest rift anywhere on Earth.

Step into the cool deep past and unknown future of who begat who.

A hidden garden of stones engraved with scriptures, a Joseph Smith Sphinx, all carved by one man.

Visitors to this library are in for a real-world education in modernist architecture.

The remains of this early 20th century refinery loom on a mountainside like a graffiti-covered fortress.

This geothermal hot spring hides beneath a slowly growing mineral dome.